Smartphones battle cameras for on-the-run picture-taking

BERLIN--Is that a phone or a camera in your pocket? As mobile phones become more camera-like by the day, it's sometimes hard to tell.

All it takes is a flick of the wrist to get a mobile out of a pocket. One click and you've got a picture. But how does the result compare to images taken with a digital camera? It's a question that will come up more and more as the popularity of mobiles boom.

The quality of smartphone pictures depends on many factors, of which resolution is only one. The majority of smartphones have cameras capable of at least 5 megapixels. But more pixels don't automatically mean better image quality.

"The size of the image sensor is also important," says Ronald Dammschneider of Stiftung Warentest, a German consumer reports agency. He notes that sensors can be very small on smartphones. In models with high resolution, that means a lot of pixels have to share a small space, which can lead to unpleasant patterns, blurry edges and dull colors.

A compact camera will tend to come with a lens, which can help for zooming in and out. For space reasons, smartphones tend to only have a digital zoom.

"The more you enlarge a picture taken with digital zoom, the more contrast you lose and the blurrier it gets," says Dammschneider. That means smartphone photography is best suited for subjects where no zooming is required.

A lot of smartphones also come with autofocus. But this just usually puts all subjects in the viewer into focus, says Wolfgang Pauler, an editor with German technology portal Chip Online. That makes it impossible to take portraits with out-of-focus backgrounds or with depth. "The autofocus in digital cameras is usually a little more sensitive."

On top of that, smartphone photography is usually done one-handed, since the other one has to touch the screen to trigger the image.

"Pictures get crooked that way pretty fast," warns Constanze Clauss of the German Photo Industry Association. Anyone who wants to take a lot of pictures with a smartphone should consider a device with a physical shutter release on the exterior housing.

"Most smartphone photos get murky at dusk or nighttime," says Tobias Haburg of the magazine Photographie. Usually you can only get good quality with close-up shots. You can, generally, forget group portraits in a dark bar or images of the nighttime skyline, says Pauler. "I don't know of any model where you can increase the exposure time."